<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            width: 100px;
            height: 100px;
            background-color: pink;
        }
        #d1{
            /*单独某一个方向赋值*/
            margin-left: 50px;
            margin-top: 50px;
            margin-bottom: 30px;
            margin-right: 50px;
            margin: 50px;/*四个方向赋值*/
            margin: 50px 100px;/*上下50 左右100*/
            margin: 10px 20px 30px 40px;/*上右下左顺时针赋值*/
        }
        #d2{
            /*外边距塌陷问题:上下相邻的兄弟元素彼此添加外边距取最大值*/
            margin-top: 50px;
        }
        /*行内元素上下外边距无效*/
        #s1{margin-right: 50px}
        #s2{margin-left: 50px}/*左右相邻彼此添加外边距两者相加*/
        #big{
            width: 200px;height: 200px;background-color: red;
            overflow: hidden;/*解决粘连问题*/
        }
        #big>div{
           width: 50px;height: 50px;
            background-color: blue;
            margin-left:50px;
            /*外边距塌陷问题导致父子元素的上外边距取最大值出现粘连的问题*/
            margin-top: 50px;
        }
    </style>
</head>
<body>
<div id="big">
    <div></div>
</div>
<span id="s1">span1</span><span id="s2">span2</span>
<div id="d1">div1</div>
<div id="d2">div2</div>

</body>
</html>